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Diamond’s are fine unless you need an airplane equivalent to a Cessna T206 or a 421. Diamonds, are really competing with Cirrus or the Cessna 172. As someone f
by briandear 5y ago
Diamond’s are fine unless you need an airplane equivalent to a Cessna T206 or a 421. Diamonds, are really competing with Cirrus or the Cessna 172.
As someone flying a 310 horsepower turbocharged 206, using an unleaded AvGas is a scary proposition. The only way to operate these turbo engines on current unleaded technology fuels would be to significantly reduce the boost pressure of the turbo and massively de-rate the engines. Flying heavy or out of hot or high airports would be significantly more dangerous. On normally aspirated 172s with a 160 or 180 horsepower engine, it would be less of a big deal. On a turbo-high performance engine, getting the performance out of the fuel is something not likely (hence the STC only for 172 lycomings.) Detonation would be the main risk or you’d have to use significantly less power which defeats the purpose. There are already mogas STCs. Until those fuels work in high performance engines, this isn’t really a groundbreaking thing.
And just a point of fact, just because lead is “scary,” the actual environmental impact of leaded AvGas is trivial — despite the flawed “studies” put forth by the anti-airport lobby. If we want to improve the environment, I am all for it, but targeting AvGas is like trying to swat a fly circling a dead elephant. One Chinese factory spits out enough toxins in a day than the entire AvGas fleet does in a year. That’s not to say we shouldn’t work for better and cleaner airplane fuels, but in terms of environmental impact, this isn’t doing much. Resources would probably be better spent on lead and asbestos remediation in old, low income housing — or in the water supply. Kids aren’t getting sick from AvGas exhaust.
- base698 5y agoHow much are your annuals?
- wffurr 5y ago>> The EPA's own studies have shown that to prevent a measurable decrease in IQ for children deemed most vulnerable, the standard needs to be set much lower, to 0.02 µg/m3. The EPA identified avgas as one of the most "significant sources of lead". Atmospheric lead is pretty dangerous, more so than encapsulated lead paint inside a wall.
- lazide 5y agoThat’s an incredibly misleading quote - do you have anything that can correlate atmospheric lead concentrations at ground level with flight hours or take/offs and landings somewhere?
- edrxty 5y agoI was curious so here's some napkin math Assumptions: - moderately busy airport, three Cessna 172s concurrently in the pattern during the day @7gph - no significant wind - 7gph3cessnas2glead/gallon=42grams of lead/hr - The lead sinks as the combustion products are far heavier than the atmosphere. To reach 0.02ug/m^3 you'd need to dilute it in approximately 1000m x 1000m x 2000m of air which is well beyond the boundaries of a typical airport of this type. Honestly this seems pretty plausible.
- lazide 5y agoHmm, thanks for doing the math! I don’t think that is that far off the boundaries of typical GA airports, and for those that are smaller they are almost always in the middle of nowhere with no inhabitants around them. One of the more concerning types of GA airports is something like Reid-Hillview, which is surrounded on all sides by residences - and even has an elementary school right on it’s border. It’s 750mx1200m - and a lot of it’s pattern is going to be over a much, much wider area. Altitude wise, it’s going to be between 1-4 thousand feet most of the time too. So it’s almost certainly going to be diluted well below that level, even if there is zero air movement, which there always is? It will be spread over a wider area of course, but if concentration is the concern, you’d probably only have higher amounts somewhere like the flight line?
- sneak 5y agoNote that the word most is not in the quote from the source.